Dust bag assembly



Aug. 4, 1959 R. c. HASTRUP DUST BAG ASSEMBLY 3 Sheets-Sheet 1 Filed May 31, 1957 ATTORNEY Aug. 4, 1959 R. C. HASTRUP DUST BAG ASSEMBLY 3 Sheets-Sheet 2 Filed May 31, 1957 INVENTOR. EOLFC. 14 145721 ATTOIZA/EY g- 4, 1959 Y R. c. HASTRUP 2,897,915

DUST BAG ASSEMBLY Filed May 31, 1957 3 Sheets-Sheet 5 INVENTOR.

revue, mar/zap ATTORNEY United States Patent This invention relates to a dust bag assembly for use in the collection of dust created during a machine operation and in which operation an air stream laden with dust is discharged by the machine, such as with certain types of abrasive blast cleaning machines and certain vacuum cleaners.

In some abrasive blast cleaning operations it is desirable to keep the surrounding atmosphere free from dust and flying particles. This is generally accomplished by drawing the debris and spent abrasive away from the surface undergoing treatment by the use of a suction air stream. In some types of machines this suction stream is created by an eductor nozzle which is fed by compressed air, the zone of entrainment for such nozzle being in communication with the surface being cleaned, so that the debris and spent abrasive are sucked into the nozzle and commingled with the air stream discharged from said nozzle, generally through some kind of tubular channel. In machines of the type described in copending application Serial Number 521,719, now Patent No. 2,840,955, this suction stream passes through a separator chamber where debris and spent abrasive are removed, the dust remaining in the air stream to enter the eductor nozzle arid be discharged therefrom through the discharge tube which leads to the dust collecting bag. In machines of the type described in US. Patent Number 2,723,498 the debris and spent abrasive along with the dust enter the entrainment zone of the nozzle and are discharged into a separator chamber where debris and spent abrasive settle out, the dust then being carried in the pressure stream through a discharge tube into the dust collecting bag. The dust bag assembly of this'invention is particularly useful with the dust discharge tube of both these types of abrasive blast cleaning machines. It is, however, useful with any type of machine using an eductor nozzle suction effect for removing dust and dirt particles, and in fact with any dust-laden air stream that may be carried through a dust discharge tube into a dust collecting bag. For example, my dust bag assembly may be used with eductor suction vacuum cleaners which are employed in industry with compressed air instead of an electric motor to drive a suction fan, such vacuum cleaners having an advantage in lighter weight together with a safety factor in being non-sparking in hazardous areas. With machines of the aforesaid types it is desirable that the dust bag be completely removable from the dust discharge tube without the necessity of separate clamps,

the use of which is generally attended with the danger that the .operator'rnay lose the parts when the bag is removed for cleaning. The dust bag ofthis invention has no separate parts,' I

. It is another object of invention to provide a dust additional opening in the bag bymeans positioned wholly within the bag, thus'providing a bag free from outside 2,897,915 Patented Aug. 4, 1959 accessory parts, which may tend to interfere with the operation of the machine, particularly in moving it about in cramped quarters.

These and other objects and advantages of the invention will appear from the ensuing description and appended claims.

One form of the invention is illustrated by way of example in the accompanying drawings and is described in detail hereinafter. The particular constructions herein shown and described are to be construed as illustrative only, and not as limiting the invention.

In the drawings:

Fig. 1 is a perspective view showing the dust bag in opened position at the beginning of its being assembled with the dust discharge tube of a machine.

Fig. 2 is a side view of the completed assembly of the dust bag and dust discharge tube.

Fig. 3 is a cross-sectional view of the assembly taken on line 3-3 of Fig. 2.

Fig. 4 is an enlarged cross-section on line 4-4 of Fig. 2.

Fig. 5 is an enlarged cross-section on line 55 of Fig. 1 wherein the neck of the bag is in partially opened position.

Fig. 6 is a side elevation view of the dust discharge tube.

Fig. 7 is an end elevation view as seen in the direction of line 77 of Fig. 6.

Fig. 8 is a fragmentary view showing thepattern of a portion of the fabric of the bag used for forming the arrangement shown in Fig. 9.

Fig. 9 is a fragmentary View of the bag turned inside out showing the arrangement of parts at the rearward end of the longitudinal opening along the side of the bag.

Referring to the drawings, a dust bag, designated generally by the numeral 10, is made of any suitable fabric or other material conventionally used for the collection of dust from dust-laden air streams. The bag is preferably tapered at its open end to form a neck and terminates at said neck in a collar band-11 provided with an elastic strap 12 having a snap fastener 12, the collar band and elastic strap being adapted to be positioned around a dust discharge tube as later described. This opening in the end of the bag is sometimes hereinafter referred to as a transverse opening in the bag. The bag 10 is formed with a longitudinal opening, designated generally as 13 (Fig. 1), along one side of its. tapered end portion, said longitudinal opening being continuous with the space between the two ends of the said collar band 11 when the bag is. in position as shown in Fig. 1. In other words, the said longitudinal opening is continuous with said transverse opening. The edge o f the fabric along each side of said longitudinal opening 13 is provided with a rib 14 which extends from the inner edge of the said collar band 11 rearwardly to a point a short dis .tance beyond theapex or rearward end 15 (Fig. 2) of said longitudinal opening 13. As the ribs approach the apex of said opening the edges of the fabric which carry said ribs are turned inwardly and downwardly so that said ribs' enter the bag at about the said apex of said longitudinal opening and thus have their rearward ends posi tioned within the bag just below the 'wall of the bag, The end of each of said ribs is formed into a freely projecting end and the two said free ends are preferably joined together by any suitable means, such as by sewing, to constitute a single projecting lead member 16. I prefer to form the said ribs by securing a cord 14, which may 'consistofany suitable Cordage or rope-like material, to the fabric along each edge of the longitudinal opening 13. The said cord may be secured by wrapping the fabric of the bag around it and folding the fabric back over itself,

as shown in Fig. 5, and then suitably sewing the two layers of fabric together. Two such seams. of said sewing are shown by the dotted lines 17 and 17' in Fig. 1 and Pi 9.

The arrangement of .the parts atthe apex of thelongitudinal opening13 in this preferred structure may. best be seen with the bag turned inside out, a fragmentary, longitudinal side view of which, in the vicinity of the apex or end 15 of the longitudinal opening 13, is shownm Figs. 8 and 9. In Fig. 9 the parts are shown as they exist in the finished bag (turned inside out), while Fig. 8 shows the pattern or shape of the fabric before it is wrapped around the cord 14 to form the finished bag. In 7 both of these views, 18 designates the edges of the fabric which are sewed together to form the main body of the bag. A flap 19 has its outer edge 20 (Fig. 8) parallel to the general direction of the aforesaid taper of the neck at the open end of the bag. The cord14 is placed against said flap in a position such that when the fiap is wrapped over the cord 14' as hereinabo e mentioned, the edge of the flap takes the position shown at20 in Fig. 9. The flap is then sewed at two seams 17 and 17 as aforesaid, seam 17 being in close proximity to the cord 14' and seam 17' spaced apart therefrom. The cords 14' as thus enclosed by the fabric of flaps 19 constitute the aforesaid ribs 14. The corresponding flap and cord for the opposite side of the longitudinal opening 13 are similarly positioned and sewed, except that they are of the opposite hand. The rearward end portions of said ribs 14 and their contained cords 14' 'are placed adjacent each other, preferably with one rib approximately above the other (as distinguished from being laterally positioned with reference to each other) and in this position the fabric of the overlapping flaps 19 which fold over the cords 14 are all sewed together by a seam 21 which is between seams 17 and 17' and which extends forwardly a relatively short distance, about an inch or an inch and one half from the rearward ends of the said ribs 14 and 14'. The end of this seam 21 thus forms the aforesaid apex or end of the longitudinal opening 13 in the bag. The sides of the fabric which constitutes the main body of the bag are sewed together along their edges 18, as by a seam represented by the dotted line 22 in Fig. 9. If desired the seam 21 may be a continuation of the seam 22. A slit 23 through all the layers of the fabric of the folded-over flaps 19 from the rearward edges thereof forwardly to a point about one-half inch or so rearwardly of the apex 15 forms the rearward end portions of ribs 14. The aforesaid lead member 16 may be constituted by suitably securing together these said rearward end portions. The bottom end portion of the bag and the side of the tapered end portion opposite the longitudinal opening 13 are closed by any suitable sewing, not shown. It will thus be seen that when the bag is turned from the inside out to its normal position, the parts shown in the fragmentary inside out view of Fig. 9 will assume the relationship hereinabove generally described for the arrangement of parts in the vicinity of the apex or end 15 of the longitudinal opening 13 when the bag is in its normal position, shown in perspective in Fig. 1, i.e., that in the normal, but open, position of the bag the ribs 14 along the two edges of the opening 13 will turn inwardly and downwardly as they approach the said apex of opening 13 and that their rearwardly projecting free ends Will be positioned within the bag and just underneath the wall thereof; and that in this position within the bag the said free ends when secured together constitute the aforesaid projecting lead member 16.

A dust discharge tube 25 serves to convey dust'from the machine used in cleaning operations into the dust bag 10. Two slender parallel rods 26, spaced apart so as to provide a narrow slot 27 therebetween (Fig. 7) throughout a substantial, but not the entire, portion of their length as measured from their outer ends, are rigidly attached to the tube 25 in a position such that, they project up- 4 wardly from, and in a direction toward the rear of said tube at an angle preferably substantially equal to the angle of taper at the open end of dust bag 10, an angle of about 25 degrees being appropriate for such purpose. In other words, the angle between the longitudinal axis of the slot 27 and the axis of tube 25 is substantially the same as the angle of taper of the sides at the forward end of dust bag 10. Near the junction of the rods 26 with the tube 25 the parallelism ceases and the rods 26 diverge from each other to form an enlarged area 28 between said rods. The slot 27 between the rods 26 thus gradually and smoothly widens into area 28, as seen in Fig. 7, this being a particularly desirable feature of the device. The object of this area 28 is to permit the entrance between the rods 26 at this point of the aforesaid lead member 16 which exists at the end of the ribs 14 near the rearward end of the longitudinal opening 13 in bag 10, and the spread between the rods at this point should be such that the said area 28 will be of appropriate dimensions therefor. The rods 26 are rigidly secured together at their outer ends 29 (Fig. 7) so that together they act as a clamping unit to hold the said ribs 14 of the bag as hereinafter explained. If desired, the two rods may constitute the two arms of a U-bend formed from a single length of rod, in which case their outer ends 29 would be automatically rigidly held together by the U-bend. The length of the rods 26 is approximately that of the ribs 14 of the bag 10 as will be seen when their clamping action is hereinafter explained.

A preferred arrangement by which the desired gradual widening and smooth transition of'the slot 27 into the enlarged area 28 is obtained is to provide that the end portion of each rod which is in rigid attachment to the tube 26 be in the form of a recurved or backwardly extending section which diverges slightly outwardly from a plane in which both the axis of the slot 27 and the axis of the tube 26 lie, the said recurved section being formed with a smoothly rounded curve at the bend where it is formed, the curvature of said bend and the amount of the said divergence of the recurved sections being such as to form the aforesaid area 28 and give to it the appropriate dimensions as aforesaid. Obviously other arrangements may be employed at the juncture of the rods 26 with the tube 25, such for example as by having the ends of the rods which are rigidly attached to the tube extend around the tube in a plane perpendicular to the .axis of the tube, not shown in the drawings, instead of being recurved toward the rear end of the tube, the rods being spread apart from their parallelism as they approach their juncture with the tube so as to provide the afore said enlarged area 28.

The operation of the device to effect the assembly of the dust bag and dust discharge tube is as follows: the tube 10 is inserted through the longitudinal bag opening 13 and positioned so that the clamp rods 26 are uppermost and extend toward the rear end of the bag as shown in Fig. l. The lead member 16 on the ends of the ribs 14 is inserted through the area 28 where it takes a position just underneath the parallel rods 26. It is then pulled along the length of the rods 26, during which operation the ribs 14 are pulled into parallel relationship with the rods 26. This pulling operation is readily accomplished by grasping the bag from the outside, in the region of the ends of cords 14 or the lead member 16, between the thumb and fingers. The fabricscomprising the flaps 19 which envelop and hold the ribs 14 are thereby. pulled into and along the slot 27, the rods 26 serving as a clamp to hold the ribs 14 and their enveloping. fabrics inv compression against each other, as shown in Figs. 3 and 4. By reason of one of the ribs 14 being positioned somewhat above the other when their ends'were'sewed together as hereinabove described, their position in relation to the clamp rods 26 will now be such that'the uppermost rib will tend tobe wedged in against both'rods 26'Witl1, the lowermostrib against one of the rods and the other of the two ribs, as also shown in Figs. 3 and 4. By this operation the bag is progressively closed throughout the full length of the longitudinal opening 13, this closure becoming complete when the lead member 16 is pulled far enough along the rods 26 that the inner edge of the collar band 11 is brought into close proximity with the area 28 at the juncture of the rods 26 with the tube 25, at which time the tube 25 within the bag has taken the position as shown in Fig. 2.. The extreme end of the bag, comprising the collar band 11, is closed around the tube 25 and held thereagainst by means of the aforesaid elastic band or strap 12 and its snap fastener 12. It will thus be seen that the clamping means afforded by rods 26 and slot 27 functions from within the bag to effect complete closure of the bag along the entire length of longitudinal opening It will also be observed that when the complete. assembly is effected, the clamp rods 26 serve additionally to hold the fabric comprising the forward end of the bag away from the dust discharge tube so as not to obstruct the flow of the dust from the tube. This is of particular advantage especially with abrasive blast cleaning machines of the portable type which are carried about by a single operator, for with the bag held with the tube horizontal and the clamp rods above the tube the fabric is prevented from hanging over the end of the discharge tube where, in the event of any abrasive particles being present in the high velocity dust stream, it would be subject to undue wear by the impact of such particles.

To cushion the fabric of the bag from being damaged by the end of the discharge tube when the machine is put down so that it rests with the bag between a hard surface and the edge of the tube, the end of tube 25 is provided with an appropriate protecting member 30 made of rubber or other suitable material.

To remove the bag the elastic strap 12 and collar band 11 are unwrapped from around tube 25 and the said tube is pushed into the bag while at the same time that part of the bag above said clamp rods is pulled along the clamp rods 26 in the opposite direction from that employed in closing the bag.

It will be seen that the bag is held in Working engagement with the dust discharge tube without the necessity of separate clamps, thus eliminating the danger of losing separate parts when the bag is removed for cleaning; that the added length of the total opening afforded by the longitudinal opening in the bag in coaction with the transverse opening at the end makes it easy to turn the bag inside out for cleaning; that the bag is closed without the use of any separate or unattached parts that might become lost when the :bag is removed for cleaning; and that the entire longitudinal opening in the bag is held closed from within the bag, thus eliminating the necessity for any outside accessories for closing the bag which might interfere with the free movement of the bag from place to place, especially when used with a portable machine in closed or hampered quarters.

While I have shown a preferred form of my invention, it is to be understood that-various changes may be made in its construction without departing from the spirit of the invention as defined in the appended claims.

I claim:

1. In a dust bag for use in the collection of dust from a machine operation in which a stream of air and dust is discharged, the combination comprising a neck band secured to said bag and adapted to fit around a dust discharge tube, said neck band when fitted around said tube having its ends-adjacent each other and defining a transverse opening into said bag, a longitudinal opening in said bag, one end of each side of said longitudinal opening being adjacent an end of said neck band, the other ends of the two sides of said longitudinal opening being joined to form an apex at the lower or forward end of said longitudinal opening, a rib in the wall of said bag along each side of said longitudinal opening to give a beaded edge to each of said sides, said ribs at their forward ends near the apex of said longitudinal opening extending inwardly and forwardly into said bag and being formed into a projecting member within said bag which extends forwardly from the apex of said longitudinal opening.

2. In a dust bag assembly used for the collection of dust from a machine operation in which a stream of air and dust is discharged, the combination with the dust bag of claim 1, of a dust discharge tube adapted to discharge an air-dust stream from said machine operation, a pair of rods, each of said rods being secured at one end to said dust discharge tube, said rods throughout the greater portion of their length being parallel to each other and spaced slightly apart to form a narrow slot therebetween, said parallel portion of said rods being positioned at an acute angle to the longitudinal axis of said dust discharge tube, the apex of said angle being toward the intake end of said tube and the open part of said angle therefore toward the discharge end of said tube, said angle being of such size and said parallel portion of said rods being of such length that the forward ends of said rods are at a substantial distance above the discharge end of said dust discharge tube, said rods as they extend from the lower end of said parallel portion toward said dust discharge tube gradually diverging from each other to form a wedge-shaped area, as seen in the direction from the intake end toward the discharge end of said tube, which tapers toward and merges into the slotted area between the parallel portion of said tubes and is of size sufficient that said projecting member of said bag can be inserted therethrough, said dust discharge tube and said rods attached thereto being of such size and length that said tube with its said attached rods is adapted to be positioned completely within said bag with the discharge end of said tube extending in the direction toward the bottom of said bag, whereby when said projecting member of said bag is inserted through said wedge-shaped area and progressively drawn along said parallel portion of said rods the walls of said bag along said longitudinal opening of said bag are drawn into said slot between said rods and held in compressive contact against each other to close said longitudinal opening, and means for closing said neck band of said bag around said dust discharge tube.

3. The apparatus of claim 2 in which the diverging parts of said rods which form the boundary of said wedge-shaped area are recurved whereby the ends attached to said tube are extending forwardly in a direction toward the discharge end of said tube.

4. In a dust bag assembly used for the collection of dust from a machine operation in which a stream of air and dust is discharged, the combination with the dust bag of claim 1, of a dust discharge tube adapted to discharge an air-dust stream from said machine operation, a pair of rods, each of said rods being secured at one end to said dust discharge tube, said rods throughout the greater portion of their length being parallel to each other and spaced slightly apart to form a narrow slot therebetween, said parallel portion of said rods being positioned at an acute angle to the longitudinal axis of said dust discharge tube, the apex of said angle being toward the intake end of said tube and the open part .of said angle therefore toward the discharge end of said tube, said angle being of such size and said parallel portion of said rods being of such length that the forward ends of said rods are at a substantial distance above the discharge endof said dust discharge tube, said dust discharge tube and said rods attached thereto being of such size and length that said tube with its said attached rods is adapted to be positioned completely within said bag with the discharge end of said tube extending in the direction toward the bottom of said bag, means for guiding the walls of said bag adjacent said beaded edges of said longitudinal opening of said bag into the slot between the parallel portions of said rods whereby when said projecting member at the apex of said longitudinal opening of said bag is moved to a position adjacent but below the lower end portion of said parallel portion of said rods and then progressively drawn along said parallel portion of said rods the walls of said bag along said longitudinal opening of said bag are drawn into said slot between said rods and held in compressive contact against each other to close said longitudinal opening, and means for closing said neck band of said bag around said dust discharge tube.

5. In a dust bag assembly for use in the collection of dust from a machine operation in which a stream of air and dust is discharged, the combination comprising a neck band secured to said bag and adapted to fit around a dust discharge tube, said neck band when fitted around said tube having its ends adjacent each other and defining a transverse opening into said bag, a longitudinal opening in said bag, one end of each side of said longitudinal opening being adjacent an end of said neck band, the other ends of the two sides of said longitudinal opening being joined to form an apex at the lower or forward end of said longitudinal opening, a rib in the wall of said bag along each side of said longitudinal opening to give a beaded edge to each of said sides, said ribs at their forward ends near the apex of said longitudinal opening extending inwardly and forwardly into said bag, a dust discharge tube adapted to discharge an air-dust stream from said machine operation, a pair of rods, each of said rods being secured at one end to said dust discharge tube, said rods throughout the greater portion of their length being parallel to each other and spaced slightly apart to form a narrow slot therebetween, said parallel portion of said rods being positioned at an acute angle to the longitudinal axis of said dust discharge tube, the apex of said angle being toward the intake end of said tube and the open part of said angle therefore toward the discharge end of said tube, said angle being of such size and said parallel portion of said rods being of such length that the forward ends of said rods are at a substantial distance above the discharge end of said dust discharge tube, said rods as they extend from the lower end of said parallel portion toward said dust discharge tube gradually diverging from each other to form a wedge-shaped area, as seen in the direction from the intake end toward the discharge end of said tube, which tapers toward and merges into the slotted area between the parallel portions of said tube, said discharge tube and said rods attached thereto being of such size and length that said tube with its said attached rods is adapted to be positioned completely within said bag with the discharge end of said tube extending in the direction toward the bottom of said bag, means adapted for inserting the lower ends of said ribs which are located along .the sides of said longitudinal opening of said bag into said wedge-shaped area between said rods whereby when said lower ends of said ribs are progressively drawn along said parallel portion of said rods the walls of said bag along said longitudinal openingof said bag are drawn into said slot between said rods and held in compressive contact against each other to close said longitudinal opening, and means for closing said neck band of said bag around said dust discharge tube.

6. In a dust bag assembly for use in the collection of dust from a machine operation in which a stream of air and dust is discharged, the combination comprising a neck band secured to said bag and adapted to fit around a dust discharge tube, said neck band when fitted around said tube having its ends adjacent each other and defining a transverse opening into said bag, a longitudinal opening in said bag, one end of each side of said longitudinal opening being adjacent an end of said neck band, the other ends of the two sides of said longitudinal opening being joined to form an apex at the lower or =fo1ward end of said longitudinal opening, a rib in the wall of said bag along each side of said longitudinal opening to give a beaded edge to each of said sides, said ribs at their forward ends near the apex of said longitudinal opening extending inwardly and forwardly into said bag, a dust discharge tube adapted to discharge an airdust stream from said machine operation, a pair of rods, each of said rods being secured at one end to said dust discharge tube, said rods throughout the greater portion of their length being parallel to each other and spaced slightly apart to form a narrow slot therebetween, said parallel portion of said rods being posgioned at an acute angle to the longitudinal axis of said dust discharge tube, the apex of said angle being toward the intake end of said tube and the open part of said angle therefore toward the discharge end of said tube, said angle being of such size and said parallel portion of said rods being of such length that the forward ends of said rods are at a substantial distance above the discharge end of said dust discharge tube, means for guiding the walls of said bag adjacent said beaded edges of said longitudinal opening of said bag into the slot between the parallel portions of said rods whereby when said forward ends of said ribs near the apex of said opening are moved to a position adjacent but below the lower end portion of said parallel portion of said rods and then progressively drawn along said parallel portion of said rods the walls of said bag along said longitudinal opening of said bag are drawn into said slot between said rods and held in compressive contact against each other to close said longitudinal opening, and means for closing said neck band of said bag around said dust discharge tube.

References Cited in the file of this patent UNITED STATES PATENTS 1,755,969 Shigyo Apr. 22, 1930 2,016,295 Replogle Oct. 8, 1935 2,347,177 Dow Apr. 25, 1944 2,739,666 Seek Mar. 27, 1956 FOREIGN PATENTS 1,124,964 France July 9, 1956 

